Full metadata
Title
The evolution of escaping ionizing radiation from galaxies and active galactic nuclei through cosmic time
Description
Reionization is the phase transition of intergalactic atoms from being neutral to
becoming fully ionized. This process began ∼400 Myr after the Big Bang, when the first
stars and black holes began emitting ionizing radiation from stellar photospheres and
accretion disks. Reionization completed when all of the neutral matter between galaxies
became ionized ∼1 Gyr after the Big Bang, and the Universe became transparent as
it is today.
Characteristics of the galaxies that drove reionization are mostly unknown. The
physical mechanisms that create ionizing radiation inside these galaxies, and the
paths for this light to escape are even more unclear. To date, only a small fraction of
the numerous searches for this escaping light have been able to detect a faint signal
from distant galaxies, and no consensus on how Reionization was completed has been
established.
In this dissertation, I discuss the evolution of the atomic matter between galaxies
from its initially ionized state, to its current re-ionized state, potential sources of
re-ionizing energy, and the theoretical and observational status of the characteristics of
these sources. I also present new constraints on what fraction of the ionizing radiation
escapes from galaxies using Hubble Space Telescope UV imaging, theoretical models
of the stellar and accretion disk radiation, and models of the absorption of ionizing
radiation by the intergalactic medium.
becoming fully ionized. This process began ∼400 Myr after the Big Bang, when the first
stars and black holes began emitting ionizing radiation from stellar photospheres and
accretion disks. Reionization completed when all of the neutral matter between galaxies
became ionized ∼1 Gyr after the Big Bang, and the Universe became transparent as
it is today.
Characteristics of the galaxies that drove reionization are mostly unknown. The
physical mechanisms that create ionizing radiation inside these galaxies, and the
paths for this light to escape are even more unclear. To date, only a small fraction of
the numerous searches for this escaping light have been able to detect a faint signal
from distant galaxies, and no consensus on how Reionization was completed has been
established.
In this dissertation, I discuss the evolution of the atomic matter between galaxies
from its initially ionized state, to its current re-ionized state, potential sources of
re-ionizing energy, and the theoretical and observational status of the characteristics of
these sources. I also present new constraints on what fraction of the ionizing radiation
escapes from galaxies using Hubble Space Telescope UV imaging, theoretical models
of the stellar and accretion disk radiation, and models of the absorption of ionizing
radiation by the intergalactic medium.
Date Created
2019
Contributors
- Smith, Brent Matthew (Author)
- Windhorst, Rogier A. (Thesis advisor)
- Bowman, Judd (Committee member)
- Borthakur, Sanchayeeta (Committee member)
- Butler, Nathaniel (Committee member)
- Mauskopf, Phillip (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
xii, 209 pages : color illustrations
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.55691
Statement of Responsibility
by Brent Matthew Smith
Description Source
Viewed on January 4, 2021
Level of coding
full
Note
thesis
Partial requirement for: Ph.D., Arizona State University, 2019
bibliography
Includes bibliographical references (pages 142-189)
Field of study: Astrophysics
System Created
- 2020-01-14 09:20:44
System Modified
- 2021-08-26 09:47:01
- 3 years 2 months ago
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